It has been a while since I wrote about our human ability to detect lying.  So, what does the accumulated research tell us?

We’ve known for a long time, despite the pop wisdom of TV shows and movies, that we humans are no better than a coin flip at detecting the lies of acquaintances and people we’ve just met.  The usual tips like watching out for ‘tells’ or noticing that someone is sweating, twitching, or avoiding eye contact are not reliable indicators of lying. We are a little better at sensing the fibs of people we have known for a long time, but even then our track record isn’t great.  Lying, sad to say, is too easy to pull off and too hard to detect.

Nonetheless, there are some ways to spot liars that are better than a 50-50 coin flip.  Let’s talk briefly about five ways to improve your lie-detection skills that you can put to work right away.

Strain the brain – If you want to trip up a liar, getting them doing something else at the same time as they are telling you that suspected fib.  A distracted brain is less able to tell lies, and more likely to make a mistake.  Get them following a complicated recipe for chocolate cake, and even if you fail to detect the lying, at least you’ll get a nice dessert. (Vrij et al., 2022)

Focus on the voice – Overall, watching people’s faces is more distracting than helpful.  It’s better to listen to the voice.  (Leach et al., 2016) Ask yourself, ‘is this person telling me the truth?’ and then wait to see what your gut tells you.  Lying for many people is a strain, and you may hear the stress in the voice.  This is not foolproof, unfortunately, because there are many reasons for stressing out, and people react in different ways to different levels of stress.  But it works better than watching the face for those twitches!

Listen for detail – Too much detail when it hasn’t be asked for is a sign of lying (Geiselman et al., 2011).  This insight comes from a meta-study (a study of 60 studies, in this case) of police, security, and other organizations trying to detect lying from witnesses, spies, criminals, and so on.  Make the person in question talk, and talk, and talk – and see if they offer unnecessary explanations and detail.  Apologies in advance for the possibility of boredom setting in.

Listen for acceleration – Another reasonably reliable sign of lying is when the liar suddenly speeds up, as if aware that they are not being convincing, and want to throw more words at the problem.  Non-liars tend to speak at an even rate of speed.  (Geiselman et al., 2011)

Lock eyes – Finally, my favorite way to reduce lying, if not absolutely detect it, is to make intense eye contact with your suspected liar and keeping looking at them (Hietanen et al., 2018).  We find it harder to lie when we are looking deep into the eyes of someone else.  This technique only works for the normal population – those of us average folks who find lying uncomfortable and only excusable when asked a question like, “does this shirt make me look old?”

None of these techniques is foolproof, and it is up to all of us to keep our eyes and ears open, check the amount of detail being offered, and listen for sudden changes in speed – all the while remembering that our lie-detection mental software is fairly feeble.  Try different techniques in different settings and see what works best for you.  Maybe we can improve the overall level of truth-telling in a society which seems hell-bent in the other direction.